Foldable test tube rack

ABSTRACT

A foldable test tube rack formed in one piece from a single sheet of plastic material. The rack is formed and shipped in flattened condition, thereby occupying minimal space for shipment and storage, and is easily folded into an erected condition at the time use is required. Because of its simplicity of structure and economy of material, the rack is inexpensive to manufacture and may be discarded following use.

United States Patent Sendra et al. Apr. 9, 1974 FOLDABLE TEST TUBE RACK3,655,110 4/1972 Eisenbach 229/25 [75] Inventors: Jose F. Sendra;Joaquim Fernandes,

both of Miami, Fla. Primary E.\aminerMorris O. Wolk AssistantExaminer-Arnold Turk [73] Asslgnee' American. Hospital Supply Attorney,Agent, or FirmDaws0n, Tilton, Fallon &

Corporation, Evanston, 111. L

ungmus [22] Filed: Mar. 21, 1973 [2]] App]. No.: 343,541 ABSTRACT 52 us.(:1 23/259, 23/292, 211/74, A foldable test tube rack formed in onepiece from a 21 1/85 single sheet of plastic material. The rack isformed and 51 1m. (:1 B0ll 9/06 pp in flattened condition, therebyOccupying [58] Field of Search 23/259, 292; 211/85, 74, minimal spacefor Shipment and storage, and is easily 211/73, 60; 264/295; 206/65 A,17; 229/25; folded into an erected condition at the time use is re-248/450 460 quired. Because of its simplicity of structure and economyof material, the rack is inexpensive to manufac- [56] References Ci dture and may be discarded following use.

1 UN TED STATES PATENTS 5 Claims, 8 Drawing Figures 1,836,138 12/1931Turner et a1 2ll/74 PATENTEDAPR 9 I974 Q SHEET 2 [1F 2 FOLDABLE TESTTUBE RACK BACKGROUND As is well known, test tube racks are commonly usedin clinical laboratories and elsewhere, wherever it is necessary tosupport conventional test tubes during reaction or during (or awaiting)observation. Such racks are normally of the non-disposable type; thatis, they are intended for relatively long term use in the laboratory. Inspecial cases, however, it is desirable to provide a disposable rackdesigned only for relatively limited use. Thus, if special tubes are tobe used in the test, or if contamination presents a special problem, orif the particular clinical test presents certain requirements for therack (as where color comparisons are to be made, or where the degree oftransparency of the tubes contents is a determinative factor), it may bedesirable to provide an inexpensive disposable rack specificallydesigned for use with a given test, and to supply such a rack along withthe reagents for performing that test.

SUMMARY This invention is concerned with an inexpensive plastic rack forsupporting a plurality of test tubes. Unlike prior racks which haveeither been relatively bulky and awkward to storeand ship or which havebeen marketed in multiple-piece disassembled condition for laterassembly by the user, the rack of this invention is formed of a singlepiece of plastic material which may be easily and quickly folded along asingle fold line into an erected condition for immediate use. In itsflattened condition, the rack may be convenientlypackaged for shipmentin a compact package which includes the tubes and reagents necessary foruse in the test. Later, when the rack is folded into erected conditionby the user, mating portions of the hinged sections are automaticallybrought into alignment and lock or hold the rack in its operativecondition. Because the entire rack may be inexpensively vacuum formedfrom a single sheet of plastic material, it may be made available atnominal cost and may be discarded after it has served the specificpurpose intended.

Other advantages and objects of the invention will become apparent asthe specification proceeds.

DRAWINGS FIG. 1 is a perspective view of a foldable test tube rackembodying the invention, the rack being illustrated in erectedcondition;

FIG. 2 is a top plan view of the rack;

FIG. 3 is a front elevational view of the rack;

FIG. 4 is a top plan view showing the rack in flat or unfoldedcondition;

FIG. 5 is an end elevational view showing the rack in unfoldedcondition;

FIG. 6 is an enlarged end elevational view illustrating the rack inerected condition and showing (in phantom) a test tube supported by therack;

FIG. 7 is a still further enlarged sectional view taken along line 7-7of FIG. 6;

FIG. 8 is a further enlarged fragmentary sectional view taken along line8-8 of FIG. 6.

DESCRIPTION Referring to the drawings, the numeral 10 generallydesignates a test tube rack having a base section 11 and a back section12. When the rack is in the assembled condition shown in FIG. 1, thebase section is intended to rest upon any suitable support surface, suchas a laboratory table or. counter. It will be observed that the basesection has a rearwardly and upwardly sloping front wall 11a, adownwardly and rearwardly sloping top wall 11b, and side or end walls11c. The lower edges of the front and side walls terminate in anoutwardly-projecting flange 13 which extends along a single plane andwhich therefore is suitable for supporting the base section upon a flattable surface. Additionally, the flange performs the function ofresisting flexure of the front and side walls and therefore rigidifiesthe entire base section, a particularly important function in view ofthe fact that the base section is of hollow construction and is open atits bottom.

When the rack is in erected condition, the back section 12 slopesgenerally upwardly and forwardly (FIGS. 1 and 6), projecting forwardlyover a substantial portion of the top wall 11b of the base section. Asso viewed, the back section provides a front wall 12a, a

top wall 12b, and end or side walls 120. The back section also providesa bottom wall 12d which is in juxtaposition with the rear portion oftop'wall 11b of base section 11 when the rack is erected. A flange 14extends along the rear edges of top and side walls 12b and and, likeflange 13, serves to rigidify the entire section with which it isintegrally formed. The upstanding back section is hollow, beingcompletely open at its rear or back side.

A plurality of wells or depressions 15 are formed in the top wall 11b ofthe base section and, in the illustration given, are arranged in auniformly-spaced series across the front portion of that wall. Each wellis spaced the same distance in front of wall 12a of the upstanding backsection 12. Section 12 is similarly provided along its front andtop'walls with a plurality of recesses 16. Each recess is axiallyaligned with one of the wells 15 so that a test tube 17 may be supportedas illustrated in FIG. 6 with its lower end resting in the well and itsintermediate or upper portion received within recess 16. When sosupported, the tube slopes upwardly and rearwardly in a stable restcondition, being braced in that position by the upstanding back section12. A plurality of such tubes may therefore be supported in spacedparallel relation. Most desirably, the shoulders 18 defining the openfront of each recess are spaced closer together than the diameter d ofthat recess and, in particular, closer than the diameter d of tube 17 tobe received therein (FIG. 7). Diameter d is, however, sufficientlylarger than diameter d to provide a free sliding fit between tube 17 andrecess 16. Therefore, a tube to be supported by the rack must be sliddownwardly through recess 16 until its lower end is seated within well15. When so supported, the tube is restrained against independentforward tipping movement.

An important aspect of the invention lies in the fact that the entirerack is formed of a single piece of flexible or bendable material.Whilethin metal might conceivably be used, plastic materials such aspolystyrene have been found particularly effective. If plastic is used,the entire rack may be formed by vacuumforming or by any other suitablemeans from a single sheet of thin-gauge plastic. Following itsformation, and prior to folding, the rack assumes the flat conditionshown in FIGS. 4 and 5 with the flanges 13 and 14 of the same. plane. Afold line 19 defines the limits of the respective sections. As shown inFIGS. 4 and 5, line 19 is straight and extends between the rear of topwall 11b and the rear of bottom wall 12d, or what will eventually becomethe bottom wall 12d of the back section 12 when that section is foldedinto its upstanding position.

To maintain the rack in its erected condition, locking lugs and recessesare formed in the respective sections. In the form illustrated, fourupstanding lugs are formed in the base section in close proximity tofold line 19. Mating recesses 21 are formed in back section 12. Thewidth of each lug 20 is slightly greater than the width of the recess inwhich it is received. Consequently, when the rack is folded into itsfully erected condition, a compressive force is exerted upon the lug andan expansive force upon the side walls of the recess to produce a tightlocking fit between the parts (FIG. 8). While locking ribs may ifdesired be formed in the lugs to mate with corresponding grooves in therecesses, it has been found that a tight locking connection iseffectively achieved by simply dimensioning the parts as described andby relying on the resilience of the material and the tensions producedtherein.

The easeand speed with which the rack may be erected is believedparticularly important in the clinical laboratory where time wasted inmanipulating or assemblying separate parts to form a rack may haveserious consequences for the patients whose tests are to be run. Sincethe two sections of the rack are integrally formed and are thereforeinterconnected along fold line 19, such sections are precisely oriented.for erection of the rack. A user, upon receiving the rack in flattenedcondition as illustrated in FIGS. 4 and 5, simply folds the sectionstogether about line 19 until lugs 20 1. A disposable test tube rackcomprising-a base section and a back section, said sections beingintegrally 7 formed from a single sheet of flexible plastic material arelodged tightly into recesses 21. The rack is then I readytor immediateuse (FIG. 1).

While in the foregoing we have disclosed an embodiment of the inventionin considerable detail for purposes of illustration, it will beunderstood by those skilled in the art that many of these details may bevaried without departing from the spirit and scope of the invention.

We claim:

and meeting along a transverse fold line, said base sectionhaving'aplurality of wells opening upwardly and being spaced apart in atransversely-extending series, said back section being foldable alongsaid line between a shipping position wherein said back section liesalong substantially the same horizontal plane as said base section and araised position wherein said back section projects upwardly relative tosaid base section, said back section being provided with a transverseseries of recesses positioned and arranged to align with said wells whensaid back section is raised, and cooperative locking means provided bysaid base and back sections for selectively locking said back section inits raised position.

2. The structure of claim 1 in which each of said recesses has adiameter slightly greater than the outside diameter of a test tubeadapted to be received therein, said back section also providing a pairof shoulders spaced apart to define an opening into each of saidrecesses, the distance between each of said shoulders being less thanthe diameter of a tube slidably receivable in said recess, whereby, saidshoulders are positioned and arranged to prevent tipping movement of atube supported by said rack without restraining sliding movement of saidtube through said recess into and out of a supported position.

3. The structure of claim 1 in which said locking means comprises a lugprovided by one of said sections and a recess formed in the other ofsaid sections, said lug and recess being equidistant from said fold lineand being positioned and arranged to frictionally engage eflch other inmating relation when said back section is fully raised.

4. The structure of claim 3 in which said lug is wider than said recessto cause slight deformation of said recess and lug when the same areforced into interlocking relation.

5. The structure of claim 3 in which a plurality of pairs of lugs andrecesses are provided by said sections in transversely-spaced relation.

* a k 1F

2. The structure of claim 1 in which each of said recesses has adiameter slightly greater than the outside diameter of a test tubeadapted to be received therein, said back section also providing a pairof shoulders spaced apart to define an opening into each of saidrecesses, the distance between each of said shoulders being less thanthe diameter of a tube slidably receivable in said recess, whereby, saidshoulders are positioned and arranged to prevent tipping movement of atube supported by said rack without restraining sliding movement of saidtube through said recess into and out of a supported position.
 3. Thestructure of claim 1 in which said locking means comprises a lugprovided by one of said sections and a recess formed in the other ofsaid sections, said lug and recess being equidistant from said fold lineand being positioned and arranged to frictionally engage each other inmating relation when said back section is fully raised.
 4. The structureof claim 3 in which said lug is wider than said recess to cause slightdeformation of said recess and lug when the same are forced intointerlocking relation.
 5. The structure of claim 3 in wHich a pluralityof pairs of lugs and recesses are provided by said sections intransversely-spaced relation.